University of Cincinnati, Division of Endocrinology and Metabolism, Cincinnati, OH, USA.
Nutr Diabetes. 2012 Feb 13;2(2):e27. doi: 10.1038/nutd.2011.23.
Because females have blunted counterregulatory responses to hypoglycemia relative to males, we hypothesized that females would have greater sensitivity to changes in lipid availability.
To assess this, we examined the feeding response to glucoprivation (2-deoxyglucose; 2DG) and lipoprivation (mercaptoacetate; MA) in age-matched male and female Long-Evans rats.
Males versus females had significantly greater food intake after 250 mg kg(-1) of 2DG, but there were no sex differences with the 750 mg kg(-1) dose of 2DG. Glucose responses to 250 mg kg(-1) of 2DG were also significantly greater in males versus females. In contrast, females had a significant increase in food intake with all doses of MA versus saline, and had significantly greater food intake compared with males at the lowest and highest doses of MA with a trend towards significance with the intermediate dose. To determine whether estradiol (E2) is the mechanism underlying this sexual dimorphism, ovariectomized females were injected with vehicle or 2 μg of E2 every fourth day to mimic the variations in across the estrous cycle. Ovariectomized females significantly increased feeding and glucose after 250 mg kg(-1) of 2DG over intact females and E2 had no effect on these responses. Although the feeding response to 2DG was not different, the glucose response to 2DG was still significantly greater in males versus ovariectomies females. However, ovariectomized females also did not increase food intake after MA, regardless of E2 treatment.
These data collectively suggest that males are relatively more sensitive to glucose deprivation and females are relatively more sensitive to lipid deprivation. Further, these data rule out a role for cyclic changes in E2 in these sex differences.
由于女性对低血糖的代偿反应不如男性强烈，我们假设女性对脂质供应变化的敏感性更高。
为了评估这一点，我们检查了年龄匹配的雄性和雌性长爪沙鼠对葡萄糖剥夺（2-脱氧葡萄糖；2DG）和脂质剥夺（巯基乙酸；MA）的进食反应。
与雌性相比，雄性在给予 250mg/kg 2DG 后进食量显著增加，但给予 750mg/kg 2DG 时则没有性别差异。雄性对 250mg/kg 2DG 的葡萄糖反应也明显大于雌性。相比之下，雌性在所有 MA 剂量下的食物摄入量均显著增加，与雄性相比，在最低和最高 MA 剂量下的食物摄入量明显增加，在中等剂量下也有显著增加的趋势。为了确定雌激素（E2）是否是这种性别二态性的机制，将去卵巢雌性大鼠每隔四天注射载体或 2μg E2，以模拟发情周期中的变化。与完整雌性相比，去卵巢雌性在给予 250mg/kg 2DG 后显著增加了进食和葡萄糖，而 E2 对这些反应没有影响。尽管 2DG 的进食反应没有差异，但 2DG 的葡萄糖反应在雄性与去卵巢雌性之间仍然显著更大。然而，无论是否接受 E2 治疗，去卵巢雌性在给予 MA 后也不会增加食物摄入量。
这些数据表明，雄性对葡萄糖剥夺相对更为敏感，而雌性对脂质剥夺相对更为敏感。此外，这些数据排除了 E2 周期性变化在这些性别差异中的作用。
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